The present invention relates to a device for sensing the size of an original document in a continuously variable magnification type copying machine.
In this type of copying machine, it is sometimes required to magnify the size of an original of other than a standard size to make a copy on a sheet of paper of a standard size. In these cases, heretofore, the magnification has been set by manually measuring the size of the original and calculating the ratio of the size of the original to the selected copy size. Alternatively, the magnification can be changed until the necessary magnification is obtained while test copying operations are repeatedly carried out. However, if the size of an original can be read automatically, then the necessary magnification can be automatically determined from the size of the copy sheet. That is, it is unnecessary to perform calculations or to use test copies.
Also, if it is required to provide a copy having a certain size when using a continuously variable magnification type copying machine, it is necessary to determine the appropriate magnification setting to achieve this copy size. However, in this case also, for the conventional copying machine there is no way other than to perform calculations as above or to make test copies, similar to the above-described case.